heres my idea (im a bit of a kitbasher, so my mind is always thinking of things like this)
		
		
	
	
		 
	
		 
	
basically, the on-comming train trips the trigger at the same time it trips the bridge mechanism, so that the cars will be allowed to proceed when the bridge is lowered
				
			 
	 
	basically, the on-comming train trips the trigger at the same time it trips the bridge mechanism, so that the cars will be allowed to proceed when the bridge is lowered
 
	 ..... if you need me to, i can type up a document to include with the object
 ..... if you need me to, i can type up a document to include with the object